The invention arises as a result of a need for less expensive lighter weight structural materials, such as panels, which require a reduced expenditure of energy to produce, transport and erect into usable structures. More particularly, the invention is looked to as a successful alternative to prestressed or reinforced concrete. The product of the invention is suitable for example for floors, walls, ceilings and even for roofs of buildings.
In its preferred form, the product has a core or slab body of vacuum glass foam completely encased in an exterior skin or cladding of high tensile strength sheet material, such as steel. The claddings on at least the two major area surfaces of the product are applied thereto in a stretched condition and after severing of the product into usage panel lengths, the contraction of the stretched claddings or facings will compress the product along two axes, longitudinally and transversely. Along the third or thickness axis of the product, it will be compressed by the atmosphere acting normal to the major area surfaces thereof. As a consequence of this, the usable product sections are prestressed on their three dimensional axes so as to have the highest possible strength to weight ratio.
Additionally, the prestressing skin renders the panel sections of the product watertight and relatively damage-resistant and suitable for interior or exterior applications in buildings. Various decorative finishings or paints may be employed on the product.
The product has excellent thermal and sound insulation properties and good corrosion-resistance due in part to the nature of the materials themselves and in part to their processing under vacuum.
A major advantage of the product compared to internally prestressed concrete lies in the relatively fast settability of the foam glass in a continuous movement casting process which would not be practical for concrete.
The net energy requirement for the product is very favorable compared to competing materials. The comparably small weight of foam glass required per usable unit of the product should require much less energy to produce than a comparable amount of concrete. Much less steel is required in the cladding than in regular reinforced concrete with reduced energy needed for the production of the steel. In conventional prestressed concrete, most of the steel's strength is used up sustaining the heavy weight of the concrete and not the content of the building or in resisting the forces of nature, and this is not true with the more efficient product of the present invention.
Finally, much less energy is needed to transport, handle and erect building materials formed according to the invention in comparison to competing materials.
Other features and advantages of the invention will become apparent during the course of the following detailed description.